Arithmetic circuitry of a roll angle estimation device estimates a roll angle, a pitch angle a pitch angular velocity of the moving body and at least one offset error of angular velocity detectors and acceleration detectors. In a current estimation operation, the arithmetic circuitry estimates the roll angle, the pitch angle, and the pitch angular velocity and the at least one offset error, based on detection values of the angular velocity detectors, detection values of the acceleration detectors, a detection value by the velocity detector, estimated values of the roll angle, pitch angle, and pitch angular velocity from a previous estimation operation, and an estimated value of the at least offset error from the previous estimation operation.
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1. A roll angle estimation device for estimating a roll angle of a moving body, comprising: first and second angular velocity detectors which detect a roll angular velocity and a yaw angular velocity respectively around first and second axes and along two mutually different directions; first, second, and third acceleration detectors which respectively detect first, second, and third accelerations along three mutually different directions; a velocity detector which detects information concerning a moving velocity of the moving body in a direction of travel of the moving body; and arithmetic circuitry configured to estimate a current value of the roll angle of the moving body, a current value of a pitch angle of the moving body, a current value of a pitch angular velocity of the moving body, and a current value of at least one offset error of the first and second angular velocity detectors and the first, second, and third acceleration detectors, based on: detection values of the roll angular velocity and the yaw angular velocity by the first and second angular velocity detectors; detection values of the first, second, and third accelerations by the first, second, and third acceleration detectors; a detection value of the information by the velocity detector; estimated previous values, from a previous estimation operation of the arithmetic circuitry, of the roll angle, the pitch angle, and the pitch angular velocity; and an estimated previous value of the at least one offset error from the previous estimation operation of the arithmetic circuitry, wherein the arithmetic circuitry estimates the current value of the pitch angle and the pitch angular velocity of the moving body by integrating d dt [ θ ω p ] = [ ω p ( - 1 / τ ) * ω p ] wherein θ is the pitch angle, ω p is the pitch angular velocity, (l/τ) represents an exponential decay factor of the pitch angular velocity; wherein the arithmetic circuitry comprises a Kalman filter which estimates the estimated current values for the roll angle, the pitch angle, the pitch angular velocity and the at least one offset error, and the Kalman filter is extended by application of an observation equation that calculates a value of vertical acceleration G z , a value of lateral acceleration G y and a value of rear-wheel speed v r based on at least the estimated value of the pitch angle θ and the estimated value of the pitch angular velocity ω p .
This invention relates to a roll angle estimation device for determining the roll angle of a moving body, such as a vehicle, using sensor data to improve accuracy and compensate for errors. The device addresses the challenge of accurately estimating roll angle in dynamic conditions, where sensor biases and environmental factors can introduce inaccuracies. The system includes two angular velocity detectors to measure roll and yaw angular velocities around two different axes, and three acceleration detectors to measure accelerations along three distinct directions. A velocity detector provides moving velocity information in the direction of travel. Arithmetic circuitry processes these inputs to estimate the current roll angle, pitch angle, pitch angular velocity, and sensor offset errors. The estimation uses previous values from prior calculations, ensuring continuous refinement. The arithmetic circuitry employs a Kalman filter, an advanced statistical method, to estimate these parameters. The filter is extended with an observation equation that calculates vertical acceleration, lateral acceleration, and rear-wheel speed based on the estimated pitch angle and pitch angular velocity. The pitch angle and pitch angular velocity are derived using an exponential decay model to account for dynamic changes. This approach enhances accuracy by compensating for sensor biases and environmental disturbances, making it suitable for applications requiring precise roll angle estimation in moving vehicles.
2. The roll angle estimation device of claim 1 , wherein the Kalman filter estimates the estimated current values for the roll angle, the pitch angle, the pitch angular velocity and the at least one offset error based on a relationship among: the detection values by the first and second angular velocity detectors; the detection values by the first, second, and third acceleration detectors; the detection value of the information by the velocity detector; the estimated previous values from the previous estimation operation of the roll angle, the pitch angle, and the pitch angular velocity; and the estimated previous value of the at least one offset error from the previous estimation operation.
This invention relates to a roll angle estimation device used in systems requiring accurate orientation measurements, such as vehicles or drones. The problem addressed is the need for precise roll angle estimation in dynamic environments where sensor data may be noisy or subject to errors like offset biases. The device includes multiple sensors: first and second angular velocity detectors to measure roll and pitch angular velocities, first, second, and third acceleration detectors to measure linear accelerations along different axes, and a velocity detector to provide velocity information. A Kalman filter processes these inputs to estimate the current roll angle, pitch angle, pitch angular velocity, and offset errors. The filter uses detection values from the angular velocity and acceleration sensors, along with velocity data, to refine its estimates. It also incorporates previous estimated values of the roll angle, pitch angle, pitch angular velocity, and offset errors from prior calculations to improve accuracy over time. This approach reduces errors caused by sensor biases and noise, providing reliable orientation data for navigation or control systems. The Kalman filter dynamically adjusts its estimates based on the relationships between sensor inputs and prior state estimates, ensuring robust performance in varying conditions.
3. The roll angle estimation device of claim 1 , wherein the arithmetic circuitry estimates the estimated current value of the pitch angle based on an estimated previous value of the pitch angular velocity from the previous estimation operation, and estimates the estimated current value for the pitch angular velocity based on the estimated previous value of the pitch angular velocity from the previous estimation operation.
This invention relates to a roll angle estimation device used in systems requiring precise angular measurements, such as aircraft, drones, or autonomous vehicles. The device addresses the challenge of accurately estimating roll and pitch angles in dynamic environments where direct measurements may be unreliable or unavailable. The core innovation involves an arithmetic circuitry that refines angle estimation by leveraging previous values from prior calculations. The arithmetic circuitry estimates the current pitch angle by using the previously estimated pitch angular velocity from the last estimation cycle. Similarly, it calculates the current pitch angular velocity based on the previously estimated pitch angle from the prior operation. This recursive approach improves accuracy by incorporating historical data, reducing errors caused by sensor noise or transient disturbances. The device likely integrates with inertial measurement units (IMUs) or other motion sensors to provide real-time angular position feedback for navigation, stabilization, or control systems. The method ensures continuous and reliable angle estimation even when direct measurements are compromised, enhancing system robustness in applications where precise orientation is critical.
4. The roll angle estimation device of claim 3 , wherein the Kalman filter estimates the estimated current values for the roll angle, the pitch angle, the pitch angular velocity and the at least one offset error based on a relationship among: the detection values by the first and second angular velocity detectors; the detection values by the first, second, and third acceleration detectors; the detection value of the information by the velocity detector; the estimated previous values from the previous estimation operation of the roll angle, the pitch angle, and the pitch angular velocity; and the estimated previous value of the at least one offset error from the previous estimation operation.
This invention relates to a roll angle estimation device used in vehicles or other systems requiring precise orientation tracking. The device addresses the challenge of accurately estimating roll and pitch angles, which are critical for stability control, navigation, and safety systems. Traditional methods often suffer from sensor noise, bias errors, and dynamic disturbances, leading to inaccurate orientation estimates. The device includes multiple sensors: first and second angular velocity detectors to measure roll and pitch angular velocities, first, second, and third acceleration detectors to measure linear accelerations along different axes, and a velocity detector to provide vehicle speed or motion information. A Kalman filter processes these sensor inputs to estimate current roll and pitch angles, pitch angular velocity, and offset errors. The filter uses a dynamic model that relates the angular velocity and acceleration measurements to the estimated states, incorporating previous state estimates to refine accuracy. By integrating multiple sensor inputs and accounting for past estimates, the device mitigates errors caused by sensor biases, noise, and external disturbances, providing reliable roll and pitch angle estimates even in dynamic environments. The system is particularly useful in automotive applications where real-time orientation data is essential for advanced driver assistance systems (ADAS) and vehicle stability control.
5. The roll angle estimation device of claim 1 , wherein the arithmetic circuitry estimates the current value for the pitch angle by integrating an estimated previous value of the pitch angular velocity over a period of time since the previous estimation operation.
The invention relates to a roll angle estimation device used in systems requiring accurate orientation measurements, such as autonomous vehicles, drones, or robotics. The device addresses the challenge of estimating roll angles in dynamic environments where direct measurements may be unreliable or unavailable. The core functionality involves using arithmetic circuitry to compute roll angles based on sensor inputs, such as accelerometers or gyroscopes, to provide real-time orientation data. The device includes a sensor interface to receive raw sensor data, which is processed to filter noise and correct biases. The arithmetic circuitry then calculates the roll angle by integrating the angular velocity over time, compensating for errors that accumulate during integration. To improve accuracy, the device may use additional sensors or reference data to correct drift. The system also estimates the pitch angle by integrating a previous pitch angular velocity value over a defined time interval, ensuring consistent orientation tracking. The invention ensures reliable roll angle estimation even in conditions where direct measurements are unstable, enhancing navigation and control systems. The integration-based approach allows for continuous updates, making it suitable for applications requiring high precision and real-time performance.
6. The roll angle estimation device of claim 5 , wherein the Kalman filter estimates the estimated current values of the roll angle, the pitch angle, the pitch angular velocity and the at least one offset error based on a relationship among: the detection values by the first and second angular velocity detectors; the detection values by the first, second, and third acceleration detectors; the detection value of the information by the velocity detector; the estimated previous values from the previous estimation operation of the roll angle, the pitch angle, and the pitch angular velocity; and the estimated previous value of the at least one offset error from the previous estimation operation.
Technical Summary: This invention relates to a roll angle estimation device used in systems requiring precise orientation measurements, such as autonomous vehicles or aircraft. The device addresses the challenge of accurately estimating roll and pitch angles in dynamic environments where sensor data may contain errors, such as offset biases in angular velocity and acceleration measurements. The device includes multiple sensors: first and second angular velocity detectors to measure rotational rates, first, second, and third acceleration detectors to measure linear acceleration, and a velocity detector to provide velocity information. A Kalman filter processes these inputs to estimate the current roll angle, pitch angle, pitch angular velocity, and offset errors. The filter uses a mathematical relationship between the sensor detection values, previous estimated values from prior calculations, and the current sensor readings to refine its estimates. The Kalman filter continuously updates its estimates by incorporating new sensor data and correcting for errors, ensuring high accuracy in real-time orientation tracking. This approach improves reliability in applications where precise roll and pitch angle measurements are critical, such as navigation, stabilization, or motion control systems. The device mitigates the impact of sensor biases and noise, providing robust performance in varying operational conditions.
7. The roll angle estimation device of claim 2 , wherein the Kalman filter comprises a saturation limiting circuit which, when any of the estimated current values exceed an upper limit value of a predetermined range, sets the estimated current value, that exceeds the upper limit value, with the upper limit value, and when any of the estimated current values is lower than a lower limit value of the predetermined range, sets the estimated current value, that is lower than the lower limit value, with the lower limit value.
A roll angle estimation device includes a Kalman filter that processes sensor data to estimate roll angles of a vehicle or other moving object. The device addresses the problem of inaccurate roll angle measurements due to sensor noise, bias, and dynamic disturbances, which can lead to unreliable estimates in navigation and control systems. The Kalman filter improves estimation accuracy by dynamically adjusting state variables based on incoming sensor data and a predictive model. The Kalman filter in this device includes a saturation limiting circuit that enforces bounds on estimated current values to prevent unrealistic or unstable outputs. If any estimated current value exceeds an upper limit of a predefined range, the circuit caps that value at the upper limit. Similarly, if any estimated current value falls below a lower limit, the circuit sets it to the lower limit. This ensures that the roll angle estimates remain within physically plausible bounds, reducing errors caused by extreme or erroneous sensor readings. The saturation limiting circuit enhances robustness by mitigating the impact of outliers or sensor faults, improving the reliability of the roll angle estimation for applications such as vehicle stability control, autonomous navigation, and inertial measurement systems.
8. The roll angle estimation device of claim 7 , wherein one of the estimated current values exceeds the upper limit value of the predetermined range, so that the saturation limiting circuit sets the one estimated value with the upper limit value, and the one estimated current value is one selected from the group consisting of the estimated current value of the roll angle, the estimated current value of the pitch angle, and an offset error of the pitch angular velocity.
A roll angle estimation device is used in systems requiring precise angular measurements, such as automotive or aerospace applications, where sensor data may be corrupted by noise or saturation effects. The device estimates roll and pitch angles, as well as an offset error in pitch angular velocity, by processing sensor inputs. However, when sensor data exceeds a predetermined range, the estimated values may become unreliable due to saturation. To address this, the device includes a saturation limiting circuit that enforces upper limit values on any estimated current values that exceed the predefined range. This ensures that the roll angle, pitch angle, or pitch angular velocity offset error does not produce erroneous outputs when sensor data is saturated. The limiting circuit selectively applies the upper limit to whichever estimated value exceeds the range, maintaining system stability and accuracy. This approach prevents degraded performance in dynamic environments where sensor inputs may fluctuate beyond expected thresholds.
9. The roll angle estimation device of claim 7 , wherein one of the estimated current values is lower than the lower limit value of the predetermined range, so that the saturation limiting circuit sets the one estimated value with the lower limit value, the one estimated current value is one selected from the group consisting of the estimated current value of the roll angle, the estimated current value of the pitch angle, and an offset error of the pitch angular velocity.
This invention relates to a roll angle estimation device for vehicles, particularly addressing inaccuracies in roll angle estimation due to sensor saturation or offset errors. The device estimates roll and pitch angles using angular velocity sensors, but these estimates can become unreliable when sensor outputs saturate or contain offset errors, leading to incorrect roll angle calculations. The device includes a saturation limiting circuit that corrects estimated current values when they fall outside a predetermined range. Specifically, if an estimated current value for the roll angle, pitch angle, or pitch angular velocity offset error is below the lower limit of the predetermined range, the saturation limiting circuit replaces that value with the lower limit value. This ensures that the roll angle estimation remains accurate even when sensor data is compromised. The device also includes a roll angle estimation circuit that calculates the roll angle based on the corrected values, improving overall system reliability. The invention is particularly useful in automotive applications where precise roll angle estimation is critical for stability control and driver assistance systems.
10. The roll angle estimation device of claim 2 , wherein the arithmetic circuitry includes low-pass filters that receive outputs from the first and second angular velocity detectors, the first, second, and third acceleration detectors, and the velocity detector, and the arithmetic circuitry treats filtered outputs, that have been transmitted through the low-pass filters, as, respectively, the detection values of the first and second angular velocity detectors, the first, second, and third accelerations detector, and said velocity detector.
A roll angle estimation device is used to determine the roll angle of a moving object, such as a vehicle, by processing signals from multiple sensors. The device includes angular velocity detectors to measure rotational motion and acceleration detectors to measure linear acceleration in different axes. A velocity detector measures the object's speed. The device processes these signals using arithmetic circuitry to estimate the roll angle accurately. The arithmetic circuitry includes low-pass filters that process outputs from the angular velocity detectors, acceleration detectors, and velocity detector. These filters remove high-frequency noise from the sensor signals, ensuring smoother and more reliable data. The filtered outputs are then used as the final detection values for further calculations. By applying low-pass filtering to all sensor inputs, the device improves the accuracy of roll angle estimation by reducing the impact of sensor noise and transient disturbances. This approach ensures that the roll angle is calculated based on stabilized sensor readings, enhancing overall system reliability in dynamic environments.
11. The roll angle estimation device of claim 1 , wherein, the moving body includes a front wheel and a rear wheel; said velocity detector includes a rear-wheel rotation speed detector which detects a rotation speed of the rear wheel as the information concerning the moving velocity of the moving body in the direction of travel of the moving body; and the arithmetic circuitry further estimates the moving velocity of the moving body, and estimates the current value of the roll angle of the moving body, the current value of the at least one offset error, and a current value of the moving velocity of the moving body, based on: the detection values of the roll angular velocity and the yaw angular velocity by the first and second angular velocity detectors; the detection values of the first, second, and third accelerations by the first, second, and third acceleration detectors; a detection value of the rotation speed by the rear-wheel rotation speed detector; an estimated previous value of the roll angle from the previous estimation operation; the estimated previous value of the at least one offset error from the previous estimation operation; and an estimated previous value of the moving velocity from the previous estimation operation.
This invention relates to a roll angle estimation device for a moving body, such as a vehicle, which accurately determines the roll angle (tilt angle) of the moving body during motion. The problem addressed is the need for precise roll angle estimation to improve stability control, particularly in dynamic conditions where traditional sensors may introduce errors due to offsets or environmental factors. The device includes angular velocity detectors to measure roll and yaw angular velocities, and acceleration detectors to measure accelerations in three axes. A rear-wheel rotation speed detector measures the rear wheel's rotation speed, providing information about the moving body's velocity in the direction of travel. The device estimates the current roll angle, offset errors, and moving velocity by processing these sensor inputs along with previously estimated values from prior calculations. The arithmetic circuitry uses these inputs to refine the roll angle estimation, compensating for sensor inaccuracies and dynamic changes. This iterative approach ensures real-time, high-precision roll angle determination, enhancing vehicle stability and control systems. The system is particularly useful in applications requiring accurate tilt detection, such as autonomous vehicles or advanced driver-assistance systems.
12. The roll angle estimation device of claim 1 , wherein, the moving body includes a front wheel and a rear wheel; said velocity detector includes a front-wheel rotation speed detector which detects a rotation speed of the front wheel, and a rear-wheel rotation speed arithmetic circuitry which estimates a rotation speed of the rear wheel from a detection value of the rotation speed of the front wheel by the front-wheel rotation speed detector as the information concerning the moving velocity of the moving body in the direction of travel of the moving body; and the arithmetic circuitry further estimates the moving velocity of the moving body, and estimates the current value of the roll angle of the moving body, the current value of the at least one offset error, and a current value of the moving velocity of the moving body, based on: the detection values of the first, second, and third accelerations by the first and second angular velocity detectors; the detection values of the first, second, and third accelerations by the first, second, and third acceleration detectors; an estimated value of the rotation speed of the rear wheel by the rear-wheel rotation speed arithmetic circuitry; an estimated previous value of the roll angle from the previous estimation operation; the estimated previous value of the at least one offset error from the previous estimation operation; and an estimated previous value of the moving velocity from the previous estimation operation.
This invention relates to a roll angle estimation device for a moving body, such as a vehicle, which accurately determines the roll angle (tilt angle around the longitudinal axis) during motion. The device addresses the challenge of estimating roll angle in real-time, accounting for sensor errors and dynamic changes in vehicle velocity. The moving body includes front and rear wheels. A velocity detection system measures the front wheel's rotation speed and estimates the rear wheel's rotation speed based on this measurement, providing information about the vehicle's travel velocity. The device uses multiple angular velocity sensors (gyroscopes) and acceleration sensors (accelerometers) to detect angular rates and linear accelerations in three axes. An arithmetic circuit processes these sensor inputs, along with previous estimates of roll angle, sensor offset errors, and vehicle velocity, to compute the current roll angle, offset errors, and velocity. The system iteratively refines these estimates, improving accuracy over time. This approach enhances stability control and safety by providing precise roll angle data, even in dynamic driving conditions.
13. A transport apparatus comprising: the moving body of claim 1 ; the roll angle estimation device of claim 1 which estimates the roll angle of the moving body; and a processing device which controls the transport apparatus using the roll angle estimated by the roll angle estimation device.
A transport apparatus is designed to monitor and control the roll angle of a moving body, such as a vehicle or robotic platform, to ensure stability and safe operation. The apparatus includes a roll angle estimation device that calculates the roll angle of the moving body in real-time. This estimation is used by a processing device to adjust the transport apparatus's movements, preventing excessive tilting or instability. The roll angle estimation device may use sensors, such as accelerometers or gyroscopes, to detect changes in orientation and derive the roll angle. The processing device then applies control algorithms to stabilize the moving body, such as adjusting suspension systems, braking mechanisms, or propulsion systems based on the estimated roll angle. This system is particularly useful in applications where maintaining a level or controlled orientation is critical, such as in autonomous vehicles, drones, or industrial machinery. The apparatus ensures that the moving body remains stable under varying conditions, reducing the risk of accidents or operational failures.
14. The roll angle estimation device of claim 1 , wherein the arithmetic circuitry comprises a saturation limiting circuit which, for each respective estimated current value of the estimated current values, determines whether the respective estimated current value exceeds an upper limit value of a predetermined range, and sets the respective estimated current value with the upper limit value when the respective estimated current value exceeds the upper limit value.
This invention relates to a roll angle estimation device for vehicles, particularly for estimating the roll angle of a vehicle based on current values derived from sensor data. The device addresses the challenge of accurately estimating roll angle in real-time while mitigating errors caused by sensor noise or extreme values that could lead to incorrect calculations. The device includes arithmetic circuitry that processes sensor data to generate estimated current values, which are then used to compute the roll angle. A key feature is a saturation limiting circuit within the arithmetic circuitry. This circuit evaluates each estimated current value to determine if it exceeds a predefined upper limit of an acceptable range. If an estimated current value surpasses this limit, the circuit replaces it with the upper limit value, effectively clamping the value to prevent excessive deviations. This ensures that only valid, bounded current values are used in subsequent roll angle calculations, improving estimation accuracy and system robustness. The saturation limiting circuit operates independently for each estimated current value, ensuring that all inputs are within a controlled range before roll angle computation. This approach helps maintain reliable performance even in dynamic driving conditions where sensor readings may fluctuate or contain outliers. The device is particularly useful in automotive applications where precise roll angle estimation is critical for stability control and safety systems.
15. The roll angle estimation device of claim 1 , wherein the arithmetic circuitry comprises a saturation limiting circuit which, for each respective estimated current value of the estimated current values, determines whether the respective estimated current value is lower than a lower limit value of a predetermined range, and sets the respective estimated current value with the lower limit value when the respective estimated current value is less than the lower limit value.
A roll angle estimation device is used in systems requiring precise determination of roll angles, such as in automotive or aerospace applications. The device estimates current values related to roll angle measurements, but these estimates can sometimes produce values outside an acceptable range, leading to inaccuracies or system instability. To address this, the device includes an arithmetic circuitry with a saturation limiting circuit. This circuit evaluates each estimated current value to determine if it falls below a predefined lower limit of an acceptable range. If the estimated value is below this limit, the circuit replaces it with the lower limit value, ensuring the output remains within the valid range. This prevents erroneous data from affecting subsequent calculations or control actions, improving the reliability of roll angle estimation. The saturation limiting circuit operates independently for each estimated current value, ensuring consistent and bounded outputs. This approach enhances system robustness by mitigating the impact of extreme or invalid measurements.
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April 22, 2015
December 10, 2019
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